MXPA99000140A

MXPA99000140A - Interface method for the preparation of copolylstercarbonate using catalyst that comprises salt of hexaalquilguanidinio and amina tercia

Info

Publication number: MXPA99000140A
Application number: MXPA/A/1999/000140A
Authority: MX
Inventors: Charles Davis Gary
Original assignee: General Electric Company
Priority date: 1997-12-23
Filing date: 1999-01-04
Publication date: 2000-06-01

Abstract

The present invention relates to: The level of anhydridecopoliestercarbonate linkages is reduced by preparing the copolyestercarbonate interfacially in a two-step method, starting from at least one aromatic dihydroxy compound and at least one dicarboxylic acid, the first step being carried out at a pH in the range of about 4.5-9.5, using the combination of a hexaalkylguanidinium salt as a phase transfer catalyst and a tertiary amine such as triethylamine, the proportion of the transfer catalyst. of phase and the tertiary amine is usually on the scale of about 1-5 and about 0.01-5.0 mole percent, respectively, based on the total aromatic dihydroxy and dicarboxylic acid used, in the second step of phosgenation, the pH is raised by at least 10 and a stoichiometric excess of phosgene of at least

Description

INTERFACE METHOD FOR THE PREPARATION OF COPOLYTERYCARCARBONATE BY MAKING CATALYST COMPRISING SALT OF HEXA CALILYGUANIDINE AND TERTIARY AMINE FIELD OF THE INVENTION This invention relates to the preparation of copolyestercarbonates, and more particularly to an improved method for their preparation by interfacial methods.

BACKGROUND OF THE INVENTION The preparation of copolyestercarbonates is known by the interfacial condensation of dihydroxyaromatic compounds with dicarboxylic acids and phosgene in an immiscible aqueous-organic medium. Ordinarily it takes place in the presence of a tertiary amine, a phase transfer catalyst, or both. The copolyestercarbonate products have properties similar to those of polycarbonates, but they are generally more ductile, especially when the ester units are derived from aliphatic acids. Among the uses currently under study for copolyestercaroons, is the manufacture of optical discs. For this purpose, it is often convenient to incorporate structural units that have intrinsic birefringence very low or even negative ^ such as the bisphenol derivatives of spiro (bis) indane, and especially 6,6 '-dihydroxy-3, 3, 3', 3 '-tetramethyl-1,1' spiro (bis) indane, in forward designated as "SBI". When SBI units are present in the polycarbonates, however, they are very brittle, the processing is difficult and it is almost essential to improve the ductility by incorporation of ester units. The interfacial preparation of copolyestercarbonates is also known. In this method of preparation, the reaction is carried out between phosgene and a mixture of an aromatic dihydroxy compound and a dicarboxylic acid (or corresponding acid chloride) in an immiscible aqueous-organic mixture. The reaction takes place under alkaline conditions and in the presence of a catalyst, typically a tertiary amine, phase transfer catalyst or combination of the two. The polymer ideally produced by this method contains ester and polycarbonate units. However, it is often found that said polymer also contains portions that incorporate anhydride bonds, which are thermally and hydrolytically unstable. It is frequently found that anhydride bonds are produced in substantial proportions under normal interfacial reaction conditions. The presence of these bonds can be minimized frequently by careful control of the pH of the reaction mixture. However, this has not been found to be true, when desired in the polymer a large proportion of acid-derived groups, for example 10 mole percent or more. U.S. Patent Nos. 5,510,449 and 5,519,105 describe processes for the preparation of polycarbonates, including copolyestercarbonates, in which a mixture of phase transfer catalyst and tertiary amine is employed. However, there is no suggestion of a method to reduce the proportion of anhydride bonds in a copolyestercarbonate. Therefore, it is of interest to adjust the reaction conditions in the interfacial preparation of copolyestercarbonate to suppress the formation of anhydride bonds, particularly when large percentages of ester groups are desired in the polymer.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides a method for interfacially producing copolyestercarbonates, which minimizes the formation of anhydride bonds. This is easily achieved by an appropriate choice of catalytic species and phosgenation conditions, and is effective even for the incorporation of ester groups in large proportions. The invention is a method for preparing a copolyestercarbonate comprising: passing phosgene, under reactive conditions including a pH in the range of about 4.5-9.5, in the constituents of a mixture comprising at least one aromatic dihydroxy compound, at least one dicarboxylic acid, at least one hexaalkylguanidinium salt as phase transfer catalyst, at least one tertiary amine, water and an organic solvent immiscible in water, the phosgene ratio being at least about 50% of the stoichiometric; and raising the pH to at least about 10 and continuing the phosgene step until a stoichiometric excess of at least 5% by weight of phosgene has been introduced.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The aromatic dihydroxy compounds used in the method of this invention typically have the formula (I) HO-A1-OH, wherein A is an aromatic organic radical. At least a portion of the total aromatic dihydroxy compounds used are generally those in which A has the formula (II) -A2-Y-A3-, "In which each of A2 and A is a monocyclic divalent aryl radical and Y is a single bond or a bridging radical in which 1 or 2 carbon atoms separate A2 and A3. The most frequent radicals A2 and A are unsubstituted phenylene, especially p-phenylene, which is preferred, or substituted derivatives thereof. The bridging radical Y is more frequently a hydrocarbon group and particularly a saturated group such as methylene, cyclohexylidene or isopropylidene, which is preferred. Thus, the most preferred bisphenol is 2,2-bis (4-hydroxyphenyl) propane, also known as "bisphenol A". It is also frequently preferred to employ a mixture of aromatic dihydroxy compounds, at least one of which is a spiro (bis) indane bisphenol, as illustrated by SBI and its 5,5'-dihydroxy isomer. SBI is usually preferred because of its particular effectiveness and relative ease of preparation. The term "bisphenol" will often be used hereinafter to refer to the preferred aromatic dihydroxy compounds which are usually spiro (bis) indane bisphenols and those having the formula 1. However, it should be understood that they can be substituted with other aromatic dihydroxy compounds, as appropriate. The dicarboxylic acid can be aliphatic or aromatic. Illustrative aromatic acids are terephthalic and isophthalic acid. Typical aliphatic acids include those containing 4 to 25 carbon atoms, including adipic acid, azelaic acid, suberic acid and 1,12-dodecane dicarboxylic acid. Aliphatic dicarboxylic acids are generally preferred for their excellent ductility-improving properties, with c6-20 acids being more preferred and sebacic acid and 1,2-dodecanedioic acid being most preferred. The phase transfer catalyst used in the method of this invention is at least one hexaalkylguanidinium salt. Exemplary hexaalkylguanidinium salts are hexaethylguanidinium chloride, hexaethylguanidinium bromide and quaternary phenolates (for example, compounds containing a hexaalkylguanidinium cation, 3 protons and a divalent bisphenol anion) which are described in the copending application as a serial number. No. 08 / 768,871. Suitable aliphatic and alicyclic tertiary amines include those having about 5 to 20 carbon atoms. Examples are triethylamine, tri-n-butylamine, N-methylpiperidine, 4-methylmorpholine and 4-ethylmorpholine. Triethylamine and N-methylpiperidine are often preferred. Water-immiscible organic solvents that can be employed in the method of the invention include chlorinated aliphatic hydrocarbons such as methylene chloride, chloroform, dichloroethane, trichloroethane, tetrachloroethane, dichloropropane and 1,2-dichloroethylene, and substituted aromatic hydrocarbons such as chlorobenzene, o-dichlorobenzene and the various chlorotoluenes. Chlorinated aliphatic hydrocarbons are preferred, with methylene chloride being the most preferred. End-blocking agents may also be present in the reaction mixture. They are typically phenols such as phenol, p-cresol and cumylphenol. In the first step of the method of this invention, phosgene is passed into a mixture of bisphenol, dicarboxylic acid, phase transfer catalyst, tertiary amine, water and organic solvent. The proportions of water and organic solvent are not critical but are typically reflected in a volume ratio of aqueous phase to organic phase in the range of about 0.2-1.1: 1. The reaction temperature are usually on the scale of approximately 15 ° -50 ° C, preferably 35-45 ° C. The proportion of tertiary amine used is not critical. Illustrative proportions are on the scale of approximately 0.01-5.0 mole percent based on bisphenol and total dicarboxylic acid. For the most part, lower amounts of compounds, N-alkyl heterocyclics such as N-methylpiperidine, than of aliphatic tertiary amines are required. It is most preferred that the tertiary amine be present in combination with the phase transfer catalyst throughout the course of the first step. If only the phase transfer catalyst is present when the reaction starts and the tertiary amine is added later, they can increase the anhydride levels in the product. • The proportion of phase transfer catalyst is also not critical. However, in general, it is found that the proportion of anhydride bonds in the product decreases with an increase in the amount of phase transfer catalyst. The amount employed is often in the range of about 1 to 5 mole percent. The pH of the reaction mixture is maintained in the range of about 4.5-9.5, preferably from about 6.5-9.0, during the first step of phosgene addition, typically by the addition of aqueous alkali such as sodium hydroxide or potassium hydroxide to neutralize the hydrochloric acid formed by reaction of the phosgene. As used herein, pH designates that of the aqueous phase of the reaction mixture. The addition of phosgene is continued in the first step until at least about • 50%, and preferably about 75-90% by weight of the stoichiometric amount. When the required amount of phosgene has been added in the first step, the pH of the reaction mixture is raised to at least about 10, preferably about 10-11, by the addition of more alkali. Then the addition of phosgene is continued until the amount total phosgene added is at least 5% and of preferably about 10-25% by weight in excess of the stoichiometric amount. When the reaction is complete, the copolyestercarbonate can be isolated by conventional means. These typically include the separation of organic and aqueous phases, washing of the organic phase with aqueous acid and / or water, and precipitation of the polymer by pouring in boiling water, by vapor precipitation or by combination with a non-solvent such as methanol. It has been found that the copolyestercarbonates prepared by the method of this invention contain much lower proportions of anhydride bonds than those prepared by other methods. This reduction in the level of anhydride bonds appears mainly attributable to the presence of the hexaalkylguanidinium salt. The level of anhydride bonds in the product can be determined by means of magnetic resonance spectroscopy Nuclear carbon 13. It can also be determined by proton nuclear magnetic resonance spectroscopy, 20 except when SBI units are present, since the chemical deviations of some of the protons in these units cause interference with those of the protons characteristic of the anhydride bonds. The invention is illustrated by the following examples.

EXAMPLES 1-5 J A series of 500 ml Morton flasks were loaded with 9.6 g (31.3 mmoles) of SBI, 5.0 g (21.9 mmoles) of bisphenol.

A, 2.2 g (9.4 mmoles) of 1,2-dodecanedioic acid, 250 mg (1.17 mmoles) of p-cumylphenol, 120 ml of methylene chloride, 50 ml of distilled water and different amounts of tertiary amine and hexaethylguanidinium bromide (1.75 mole percent, based on bisphenols and dicarboxylic acid). Phosgene was passed in mixtures, with stirring, at 0.25 g / min, maintaining the pH at 8 (examples 1-4 and controls 1-4) or 9 (example 5 and control 5) by the addition of aqueous sodium hydroxide solution to the % Having added 85 mole percent of the stoichiometric amount of phosgene, the pH was raised to 10.5 and the the addition of phosgene until an excess of 20 mole percent has been introduced. The organic and aqueous phases were separated and the phase ^^ organic was washed with aqueous solution of hydrochloric acid and 4 times with distilled water. The copolyestercarbonates are They were precipitated by pouring the methylene chloride solution into boiling water in a mixer, and they were filtered off, washed with water and dried at 120 ° C under vacuum. The results are given in the following table, in comparison with several controls. The following 25 abbreviations are used for the amines and the phase transfer catalysts: abbreviations for amines and phase transfer catalysts: HEGBr - hexaethylguanidinium bromide, HEGBPA - triazide hexaphenylguanidinium salt of bisphenol A, MTBA - methyltri-n-butylammonium bromide, BTMA - benzyltrimethylammonium chloride, NMPP - N-methylpiperidine, TEA - triethylamine Phase Transfer Catalyst Tertiary Amina Moles Moles Links Example Identity o ^ * o Identity% anhydride% 1 HEGBr 3.5 TEA 1.6 0.8 2 HEGBPA 3.5 TEA 1.6 0.8 3 HEGBr 1.75 TEA 1.6 1.4 4 HEGBr 1.75 NMPP 0.03 < 0.5 5 HEGBPA 3.5 TEA 1.6 0 Control 1 MTBA 3.5 TEA 1.6 4.0 Control 2 BTMA 3.5 TEA 1.6 2.2 Control 3 MTBA 1.75 TEA 1.6 2.3 Control 4 MTBA 1.75 NMPP 0.03 < 0.5 Control 5 MTBA 1.75 NMPP 0.03 < 4.0 It is evident that the level of anhydride bonds in Examples 1-4 was significantly higher. low that in one difference. However, it is believed that a difference can be observed at lower levels of phase transfer catalyst and / or tertiary amine.

Claims

NOVELTY OF THE INVENTION CLAIMS

1. - A method for preparing a copolyestercarbonate comprising: passing phosgene, under reactive conditions including a pH in the range of about 4.5-9.5, in the constituents of a mixture comprising at least one aromatic dihydroxy compound, at least one acid dicarboxylic acid, at least one hexaalkylguanidinium salt as phase transfer catalyst, at least one tertiary amine, water and an organic solvent immiscible with water, the phosgene ratio being at least about 50% stoichiometric; and raising the pH to at least about 10, and continuing the phosgene step until a stoichiometric excess of at least 5% by weight of phosgene has been introduced.

2. A method according to claim 1, characterized in that the aromatic dihydroxy compound is bisphenol A.

3. A method according to claim 1, characterized in that the aromatic dihydroxy compound is a mixture of bisphenol A and 6,6. '-dihydroxy-3, 3, 3', 3 '-tetramethyl-1,1'-spiro (bis) indane.

4. A method according to claim 1, characterized in that the dicarboxylic acid is an aliphatic dicarboxylic acid.

5. A method according to claim 4, characterized in that the dicarboxylic acid is sebacic acid or 1,2-dodecanedioic acid.

6. A method according to claim 1, characterized in that the organic solvent is a chlorinated aliphatic hydrocarbon.

7. A method according to claim 6, D ^ characterized in that the organic solvent is methylene chloride.

8. A method according to claim 1, characterized in that the tertiary amine is triethylamine or N-15 methylpiperidine.

9. A method according to claim 1, characterized in that the phase transfer catalyst is tt ^ ^ hexaethylguanidinium chloride.

10. - A method according to claim 20 1, characterized in that the phase transfer catalyst is hexaethylguanidinium bromide. 11.- A method in accordance with the claim 1, characterized in that the phase transfer catalyst is the triacid hexaetylguanidinium salt of bisphenol A. 12. A method according to claim 1. 1, characterized in that the catalyst proportion of Phase transfer is on the scale of approximately 1 to 5 mole percent, fl 13. - A method in accordance with the claim 1, characterized in that the proportion of tertiary amine is on the scale of approximately 0.01-5.0 mole percent. 14. - A method according to claim 1, characterized in that the pH is maintained on the scale of approximately 6.5-9.5 during the first step. 15. - A method according to the claim 10 1, characterized in that the addition of phosgene in the first step tt ^^ is continued until approximately 75-90% by weight of the stoichiometric amount has been added. 16. - A method according to claim 1, characterized in that the pH in the second step is in the 15 scale of approximately 10-

11. 17.- A method according to the claim 1, characterized in that the total amount of added phosgene tt ^^ is about 10 to 25% in excess of the stoichiometric amount. 18. A method for preparing a copolyestercarbonate comprising: passing phosgene, under reactive conditions including a pH in the range of about 6.5-9.5, in a mixture comprising: at least one aromatic dihydroxy compound selected from the group consisting of of bisphenol A and A mixture of bisphenol A and 6,6 '-dihydroxy-3,3,3' 3 '-tetramethyl-1,1'-spiro (bis) indane, at least one dicarboxylic acid aliphatic of g_2o- water and methylene chloride, in the presence of both: at least one hexaalkylguanidinium salt and a flB phase transfer agent, as well as: at least one tertiary amine, the proportion of said salt being 5-hexaalkylguanidinium to the tertiary amine, on the scale of about 1-5 and 0.01-5.0 mole percent, respectively, based on the total aromatic dihydroxy compound and dicarboxylic acid, and the phosgene ratio being at least about 50% on. weight of the ^ ß stoichiometric; and raising the pH to at least about 10, and continuing the phosgene step until a stoichiometric excess of at least 5% by weight of phosgene has been introduced. 19. A method in accordance with the claim 15 18, characterized in that the hexaalkylguanidinium salt is hexaethylguanidinium bromide, hexaethylguanidinium chloride, or the tri-acid hexaetylguanidinium salt of bisphenol A. ^^ 20. A method according to claim 18, characterized in that the tertiary amine is triethylamine or 20 N-methylpiperidine.